RAPID: Hurricane Impact on Phytoplankton Community Dynamics and Metabolic Response

RAPID：飓风对浮游植物群落动态和代谢反应的影响

• 批准号: 1760620
• 负责人: Lisa Campbell
• 金额: $ 19.4万
• 依托单位: Texas A&M University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-11-01 至 2019-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1760620&HistoricalAwards=false
• 关键词: RAPID; Hurricane; Impact; Phytoplankton; Community

Hurricane Harvey is the strongest hurricane to hit the Texas coast in decades and the resulting tidal surges, flooding and terrestrial runoff have had a severe impact on the coastal ocean. The effects on the phytoplankton, the first link in the food chain, may be unprecedented. To determine how the phytoplankton community will respond to such drastic changes in salinity, nutrient inputs, and potential toxins, immediate and continuous sampling is the only way to fully capture the effects and to identify when conditions return to "normal". An automated, continuous phytoplankton imaging instrument that is deployed on the Texas coast records images of the phytoplankton and permits calculation of the abundance of different species. Together with molecular information on the genes that have been "turned on", or expressed, outcomes of this project will help determine the responses of individual types of phytoplankton. Extreme storms are expected to increase in frequency with future climate change, so the responses identified now will be valuable in predicting how such events will affect these primary producers, which in turn support most of the food webs in marine ecosystems, in the future.High temporal resolution observations from the Imaging FlowCytobot (IFCB) have revealed that hurricanes in the Gulf of Mexico cause drastic changes in the phytoplankton community structure. The objectives of this RAPID project are: 1) to characterize the dynamics of the phytoplankton species in relation to the environmental variables along the Texas coast; 2) to assess the short and long-term changes in the phytoplankton community; and 3) to identify the strategies of the phytoplankton community for resource acquisition. To accomplish these objectives, this project will utilize IFCB time series to follow phytoplankton community structure during the recovery period from Hurricane Harvey. In addition, two RAPID response cruises (in late September and early October) to sample at 5 sites along a transect from Galveston to Port Aransas, TX. At each station, CTD profiles and water samples from surface and the chlorophyll maximum will be collected for nutrients, carbonate chemistry, and RNA sequencing for metatranscriptomic analysis. Metatranscriptomics can provide an indication of the metabolic strategies employed and functional relationships within the plankton community in response to changes in the environment. The advantage of a metatranscriptomic approach is that the entire molecular response to the environment is captured. So, while the response of phytoplankton to increased nutrient inputs from floodwater runoff is targeted, the responses to other environmental stresses (toxics, hypoxia, acidification) are also captured. Analyses of this time series using multivariate statistical techniques, such as principal component analysis (PCA), and network analysis, a powerful technique for identifying potential interactions among taxa, will provide insights on the environmental factors and metabolic responses structuring the community during the aftermath of the hurricane.

飓风哈维是数十年来袭击德克萨斯州海岸的最强飓风，由此产生的潮汐涌动、洪水和陆地径流对沿海海洋产生了严重影响。对食物链第一环浮游植物的影响可能是前所未有的。为了确定浮游植物群落如何应对盐度、养分输入和潜在毒素的剧烈变化，立即和连续采样是充分捕捉影响并确定条件何时恢复“正常”的唯一方法。部署在德克萨斯州海岸的自动连续浮游植物成像仪器记录浮游植物的图像，并允许计算不同物种的丰度。连同已“开启”或表达的基因的分子信息，该项目的结果将有助于确定浮游植物个体类型的反应。预计极端风暴的频率将随着未来的气候变化而增加，因此现在确定的响应对于预测此类事件将如何影响这些初级生产者非常有价值，而这些初级生产者反过来又支持未来海洋生态系统中的大部分食物网。成像流细胞机器人（IFCB）的高时间分辨率观测表明，墨西哥湾的飓风导致浮游植物群落结构发生巨大变化。 该 RAPID 项目的目标是： 1) 描述德克萨斯州海岸浮游植物物种与环境变量相关的动态特征； 2）评估浮游植物群落的短期和长期变化； 3）确定浮游植物群落获取资源的策略。为了实现这些目标，该项目将利用 IFCB 时间序列来跟踪飓风哈维恢复期间的浮游植物群落结构。此外，还进行了两次快速响应巡航（9 月底和 10 月初），在从加尔维斯顿到德克萨斯州阿兰瑟斯港的断面沿线的 5 个地点进行采样。在每个站点，将收集来自地表和叶绿素最大值的 CTD 剖面和水样，用于营养物质、碳酸盐化学和 RNA 测序，以进行宏转录组分析。宏转录组学可以指示浮游生物群落响应环境变化所采用的代谢策略和功能关系。宏转录组学方法的优点是捕获对环境的整个分子反应。因此，虽然浮游植物对洪水径流养分输入增加的反应是有针对性的，但对其他环境压力（有毒物、缺氧、酸化）的反应也被捕获。使用主成分分析 (PCA) 等多元统计技术和网络分析（一种用于识别类群之间潜在相互作用的强大技术）对该时间序列进行分析，将提供有关飓风过后构建群落的环境因素和代谢反应的见解。